Process for preparing fast black dyeings on textile material of polyethylene terephthalate



3,036,875 Patented May 29, 1962 PROCESS FOR PREPARING FAST BLACK DYE- INGS N TEXTILE MATERIAL OF POLYETHYL- ENE TEREPHTHALATE Paul Schlack, Leitershofen, Augsburg-Laud, and Franz Kienhofer, Frankfurt am Main, Germany, assignors to Farbwerke Hoechst Aktiengesellschaft vormals Meister Lucius & Briiuing, Frankfurt am Main, Germany, a corporation of Germany No Drawing. Filed Jan. 14, 1958, Ser. No. 708,753 Claims priority, application Germany Jan. 15, 1957 Claims. (Cl. 8-32) It is difiicult to -produce fast black dyeings on fibrous material of high-melting linear polyester-s containing sixmembered carbocyclic rings, for instance on highly polymeric ethylene-glycol-terephthalate. Especially, when thermally fixed goods are concerned, it is in most cases not possible to achieve success, if the goods are dyed under atmospheric pressure by means of suspension dyestuffs with simultaneous use of carriers. In general, only deep grey tints are obtained and even these require large amounts of dyestuffs and auxiliary agents. In other cases, deeper shades are obtained but the fastness properties are not satisfactory. Usually, an undesired long dyeing period of several hours is necessary.

Now we have found that very fast black tints can be obtained, within a short time in a simple and economical manner, on textile material of high-melting linear polyesters containing six-membered carbocyclic rings by applying polynuclear, especially binuclear black bases suitable for oxidation dyeing and allowing them to be absorbed by the textile material and by developing the dyeing in the presence of acids by means of hypohalogenous acids or substances hydrolytically splitting oil these acids or with chlorite. Instead of uniform black bases, mixtures thereof or mixtures with other mononuclear bases appropriate for black dyeing or toning can be used. There come into consideration bases, such as: 4-amino-diphenylamine, 4-metl1yl-4'-amino-diphenylamine, 2,4'-diaminodiphenylamine, 2methoxy-4-amino-diphenylamine, 3- methoxy-4-amino-diphenylamine and the like, as Well as mixtures of such bases with benzidine, p-tolidine, p-dianisidine, 1,8-diamino-naphthalene, 1,5-diamino-naphthalene, furthermore p-phenylene-diamine, p-aminophenol, m-phenylene-diamine, m-aminophenol, o-phenylenediamine, ot-naphthylamine Organic derivatives of the hypohalogenous acids showing ailinity to the material, is. compounds capable of hydrolytically splitting olf hypohalogenous acid, suitable to be applied on and absorbed by the fiber from an aqueous solution or dispersion and giving off this hypohalogenous acid in the fiber, i.e. acting as oxidizing agent, have proved to be particularly suitable for developing the dyeings. There can be used, for instance, substances, such as N chloro-carbamic acid ethyl ester, N-bromo-carbamic acid ethyl ester, esters of the hypohalogenous acids, especially those containing tertiary alcohols, N-ha-logen-compounds from cyclic imides, such as N-bromo-succinimide, espe cially benzene sulfonic acid monoand dichloramide, for example benzene-sulfonic acid dichloramide, p-chlorobenzene-sulfonic acid dichloramide, the sodium salt of ptoluene-sulfochloramide, N,N'-tetrachloro-l,3-dimethylbenzene-4,6-disulfonic acid amide. The optimum amount of oxidation agents with a view to efficiency and economy can easily be determined by serial tests. In general, such quantities are sufiicient as, with a goods-to-liquor ratio of 1:50, correspond to a content of 0.5-2 grams of active chlorine per liter. This applies to the organic derivatives of the hypohalogenous acids as well as to the use of hypochlorite bleaching solutions, appropriately showing a weakly acid reaction. Also when using chlorites, for example alkali metal or alkaline earth metal chlorites, such as sodium or calcium chlorites, quantities of the same range are used as regards efllciency. The indicated quantities, however, may likewise be considerably increased without fear of damage to the material. It must be ex amined in each individual case to what extent the shade is unfavorably influenced by large excesses at the temperature chosen for each case, since such alterations depend on various factors, for instance on the constitution of the fibers as regards density of structure.

When materials are to be dyed which in addition to polyester fibers contain other sensitive fibrous substances, particularly cellulose material, the oxidation with chlorite or with N-halogenyl compounds, preferably with sulfonic acid-N-chloramides is particularly recommended. Whereas a weak acid reaction is recommended when operating with hypochlorite solution, the organic derivatives of hypohalogenous acids can still be used in the neutral or weakly alkaline medium. Also in this case an acid reaction is, however, preferred.

In the practical realization of the process the material to be dyed consisting, for instance, of loose flocks, combed material, fibers, yarns, knit goods, bands, fabrics or mixed fabrics is treated at a temperature between and C., favorably in the presence of a carrier, orin the absence of a carrier-at a temperature above 100 C., under pressure, with a dispersion of the base or mixture of bases, for instance a mixture of diphenyl black base and o-toluidine. This process can also be applied in an analogous manner for the treatment of foils.

In the case of relatively easily soluble bases the solutions of the salts of the bases can likewise be used. It is favorable in such a case to take care for a gradual increase of the pH value of the bath. Naturally, it is possible to use for the first coat of the material standing baths which must be continuously supplemented, particularly when only a uniform base, such as diphenyl black base is used. It is also possible to pad the solutions on the textile material, favorably after addition of a thickening agent, whereupon the material is steamed in order to fix the dyeing.

As carriers are suitable most of the products practically used for dyeing, for instance substances, such as ophenyl-phenol, diphenyl ether, tetralin, chlorobenzene and particularly diphenylene oxide. It is desirable to avoid agents whose oxidation products unfavorably afiect the resistance to light of the dyeing and/or the shade. When high molecular and low molecular bases are combined, the latter may act as carriers. As dispersing agents for the bases and carriers there are appropriate numerous known auxiliary agents, for example alkyl-sulfates, alkylbenzene-sulfates, alkyl-sulfimides or sulfocarbon-imides and oxyethylated alkyl phenols and their semi-esters with sulfuric acid. It may be advisable to add protective colloids, such as glue. 7

It is, however, of special advantage, when dyeing with the base, to add cation active auxiliary agents to the solution which is at first acid. Thereby the pH value of the bath is raised to about 5 only by addition of an alkali metal compound showing a buffer effect, such as s0- dium phosphate, and the pH value then gradually rises to 9 by adding alkali metal hydroxide during the dyeing and impregnating operation. When operating in this manner, for which the very eifective diphenylene oxide is particularly suitable as carrier, the formation of stains due to greasy precipitates in the bath is avoided. This is of utmost importance especially for the dyeing of piece goods. It has been found that from the numerous cati onic dispersing agents those are well suitable which in addition to the cationic group contain at least one amide group. Particularly good results are obtained by typical onium compounds with, for instance, one quaternary ammonium group wherein the nitrogen may also be a member of a heterocyclic ring system. Sulfonium and phosphonium compounds and likewise guanidines are effective in an analogous manner, but tertiary bases also enter into cnsid;ration as long as they still remain dissolved or finely dispersed in water at the pH value applied. In these cationic compounds there should be contained a higher paraffinic or carbocyclic hydrocarbon radical with at least carbon atoms, preferably with 14-22 carbon atoms. In detail there may be mentioned: Methylsulfate of the monostearoyl-amidoethylene-trimethyl-ammonium-hydroxide, stearamido-propyl-dimethyl-fi-hydroxy-ethyl-ammonium-dihydrogen phosphate, N- octadecyl-N- -dimethyl-amino-propyl-urea, N-y-dimethyl-amino-propyl-palmitic acid amide, N-octa-decyl-acetamide-w-pyridinium-chloride. The reaction products of the N-[chloracetyl]-octadecyl-amine with other bases or pseudo bases, such as trimethyl amine, dimethyl-sulfide and dimethyl-ethyl-phosphine can likewise be used. As quaternary compounds containing more than one amidenitrogen atom, there are mentioned oxamides obtained by further reacting the reaction products of higher primary amines, such as dodecylamine, hexadecylamine, octadecylamine with excessive oxalate (oxamide acid ester) with primary-secondary or primary-tertiary diamines, such as ,9-diethyl-amino-ethylamine, -morpholino-propylamine or -y-piperidino-propylarnine in order to obtain the oxamide. If necessary, the products can still be quaternized. Simple quaternary ammonium salts without amide groups, for example dimethyl-octadecyl-ben- Zene-ammonium-chloride and similar bases are likewise effective, but in these cases larger amounts are generally necessary. Instead of the cationic compounds with a primary or tertiary amine or ammonium-nitrogen there can likewise be used basic urea derivatives, for instance the guanidines and biguanidines, such as penta-decylguanidine, the guanidines from mono-stearoyl-ethylene diamine and mono-hydroxy-ethyl-octadecylamine and S- methyl-isothiourea. Usually, the amount of the cationic additions can be very small and may vary between 0.1 and 5 grams/liter. Ordinarily, amounts of 0.2 to 1 gram/ liter are sufficient for a good efficiency. When larger amounts are concerned, the addition of a defrothing agent may be advisable, particularly when dyeing in the open bath. Mixtures consisting of anionic and cationic agents can also be used, if they are applied in the form of salts and have been rendered sufficiently soluble in water by introduction of appropriate substituents, for example oxyethylation at the nitrogen atom.

The oxidation takes place with hypochlorite solutions made weakly acid, at a low temperature, preferably within the range of 30 to 70 C., according to the concentration. The oxidation with chlorite and acetic acid is best carried out at the boil. In the case of organic derivatives of hypohalogenous acids the temperature of the baths must be adapted to the stability of these substances. Unstable compounds are applied to the fiber at a temperature as low as possible and only gradually in creasing, whereas relatively stable oxidation agents, such as the N-halogen compounds of the organic sulfamides are applied on and absorbed by the fiber at about 60- 80 C., whereupon the oxidation is finally achieved favorably at the boiling temperature.

At a temperature of 100 C., the development of the dyeing is usually reached within quite a short time, in most cases within a few minutes, whereas in the case of bleaching solutions prolonged treating periods are recommended. Finally, the duration of the oxidation depends on the reactivity of the bases, on the depth of the desired shades, the diameter of the fiber and the conditions of the fiber as regards orientation and crystallinity.

An advantageous variation of the process consists in starting the oxidation at a low temperature by means of hypochlorite solution and adding thereto a compound capable of being halogenated at the nitrogen atom, showing affinity to the fiber at least as halogenyl compound, especially an aromatic sulfamide, then gradually increasing the temperature, whereupon the N-halogenyl compound which has been formed in the mzantime becomes effective at an elevated temperature. Naturally, it is likewise possible to operate with mixtures of bleaching solution and a preformed halogenyl compound, such as the sodium salt of toluene-4-sulfonic acid-N-chloramide.

After dyeing, the material is thoroughly rinsed hot with a detergent, for instance an alkyl-aryl-polyglycol ether, suitably with addition of a small amount of hydrogen peroxide, for instance 0.5 gram per liter of hydrogen peroxide of 30% strength. The pH value of this cleaning bath should advantageously amount to about 7.5.

A special method of operation consists in applying the base or mixture of bases on unstretched or slightly stretched threads, for instance preformed by plastic stretching, the oxidation taking place during or after the orienting stretching. The 'base can also be applied without considerable orientation during a stretching or elongation process, for instance in connection with the aforementioned plastic stretching. When dyeing unstrstched or only partly stretched material which can be carried out with or without tension, also continuously with fixation of the base by steaming, it is, in general, not necessary to use carriers; in most cases it is even better to operate without carriers.

Although it is known that good black dyeings can be obtained on artificial acetate fibers soluble in acetone by oxidation of p-amido-diphenylamine, it could not be deduced therefrom that deep and extraordinary fast black dyeings can be produced relatively easy and at low costs on the fibers of highly polymeric polyesters, such as polyethylene glycol terephthalate, which are much more hydrophobic and considerably denser, by oxidation of pamino-diphenylamine and similar bases.

It is further known from the literature that grey and brown tints can be obtained by using certain oxidizable dyestuffs. As oxidation agents bichromate or hydrogen peroxide have been used in the cases cited. The process of the present invention, however, could not be deduced from this literature, since black dyeings and the oxidation agents applied for the process of the present invention are not mentioned.

The following examples serve to illustrate the invention but they are not intended to limit it thereto.

Example 1 4.39 grams of a thread consisting of polyethylene glycol terephthalate fibers (individual titer of the fiber fixed by steaming at 110 C.: 3.0 deniers) after having been preliminarily washed in a bath containing 2 grams/liter of a non-ionogenous alkylphenyl polyglycol ether and 0.5 gram/ liter of sodium carbonate are treated for 15 minutes at C. and a goods-to-liquor ratio of 1:50 in a bath containing 15% of p-amino-diphenyl-amine (referred to thepolyethylene glycol terephthalate), 3 grams/liter of o-phenyl-phenol and 1.5 grams/liter of an anion-active alkylphenyl polyglycol ether sulfate and, for the stabilization of the dispersion, a small amount of glue. The pH value of the bath is adjusted to 8.5 by means of dilute sodium hydroxide solution. After a treatment of 2 hours at the boiling temperature and an intermediate rinsing, the dyeing is developed in a bath containing 4 grams/ liter of the sodium salt of toluene-4-sulfonic acid-N-chloramide and adjusted to a pH of 4 by means of acetic acid. The goods are introduced into the oxidation bath at 60 C. and oxidized for 15 minutes at the boiling temperature. A good black dyeing showing a reddish tint is obtained.

Example 2 4.32 grams of a thread consisting of polyethylcne-gly- 'col-terephthalate fibers (individual titer 3.0 deniers, staple length 100 mm., Nm. 48/2, twist of thread Z 554/8 550) fixed in dry state at 195 C. without tension and, as indicated in Example 1, preliminarily washed are introduced into a dyeing bath heated to 65 C., containing 12% of p-amino-diphenylamine, 3% of o-tolidine dispersed with 1.5 gram/liter of an anion active alkylphenyl-polyglycol ether sulfate, 4 grams/liter of diphenyl ether as carrier and 0.5 gram of glue as protective colloid. The mixture of bases is applied in the same manner as described in Example 1, but a slight amount of ammonium vanadate is added as catalyst to the oxidation bath. A black tint somewhat less deep than that described in Example 1 and showing a greenish tint is obtained.

Example 3 4.4 grams of the thread described in Example 1 are treated in a bath adjusted to a pH value of 8.5 containing as carrier 12% of p-amino-diphenylamine, 3% of pphenylenediamine and 3 grams/liter of o-phenylphenol dispersed by means of 1.5 gram/liter of an anion active alkylphenyl-phenolpolyglycol ether sulfate and 0.5 gram of glue. The goods-to-liquor ratio amounts to 1:50. After a treatment of 2 hours at the boiling temperature and a short intermediate rinsing the dyeing is developed as indicated in Example 1. A deep black dyeing is obtained.

Example 4 4.25 grams of the thread indicated in Example 1 but fixed by steaming at 135 C. are treated with 12% of p-amino-diphenylamine and 3% of benzidine as described in the above examples. Composition of the dyeing bath, duration of treatment and temperature comply with the manner of operating described in Example 3. The oxidative development of the dyeing is carried out in the manner described in Example 1. A good deep black dyeing is obtained.

Example 5 4.27 grams of the thread mentioned in Example 1 are preliminarily treated with 12% of p-aminodiphenylamine and 3% of p-aminophenol. The composition of the dyeing bath and the manner of operation correspond to that indicated in Examples 3 and 4. The oxidation takes place by means of 4 grams/liter of the sodium salt of toluene-4- sulfonic acid-chloramide at a pH of 4 and with addition of a very small amount of ammonium vanadate as oxidation catalyst.

The black dyeing obtained is a little less intense than the dyeing resulting from the manner of operation described in Examples 3 and 4 and shows a bluish tint.

Example 6 3.26 grams of an unbleached fabric consisting of polyethylene glycol terephthalate yarn (poplin, warp and woof Nm. 125/2, of individual fibers of a titer of 1.2 denier, staple length 40 mm. yarn steamed for 30 minutes at 120 C. in the vacuum, thread steamed for 20 minutes at 120 C. in the vacuum) are introduced at 65 C. into 50 parts of a bath containing 12% of p-amino-diphenylamine, 3% of 2.4'-diamino-diphenylamine and 3 grams/liter of diphenyl ether and as dispersing agent 1.5 grams/liter of an anion active alkylphenyl-polyglycol ether sulfate as well as 0.5 gram/liter of glue; all quantity indications are referred to the polyethylene glycol terephthalate material. The material is treated for 2 hours at the boiling temperature in this bath which is adjusted to a pH of 8.5 by means of sodium hydroxide solution. After an intermediate rinsing with cold water the dyeing is developed at a goodsto-liquor ratio of 1:50 in a sodium-hypochlorite solution containing per liter 0.9 gram of active chlorine and adjusted to a pH value of 4. Oxidation takes place at first for 20 minutes at 65 C. and subsequently for a further minutes at the boiling temperature. A deep, fast black dyeing is obtained.

Example 7 4.3 grams of the thread indicated in Example 1 are treated for 2 hours at the boiling temperature and a goods-to-liquor ratio of 1:50 in a bath whose pH value has been adjusted to 8.5 and which contains 12% of pamino-diphenylamine, 3 grams/liter of diphenyl ether, 1.5 gram/liter of an anion active alkylphenyl-polyglycol ether sulfate and 0.5 gram/liter of glue. After a short intermediate rinsing the hanks are oxidized at a goods-toliquor ratio of 1:50 and a pH of 4 in a bath containing sodium hypochlorite corresponding to a quantity of 0.3 gram/liter of active chlorine and the sodium salt of toluene-4-sulfonic acid chloramide corresponding to a quantity of 0.6 gram/liter of active chlorine. As oxidation catalyst a small amount of ammonium vanadate is added to the bath. The oxidation is carried out at first for 10 minutes at 65 C., finally for a further 10 minutes at the boiling temperature. A deep, neutral black dyeing is obtained.

Example 8 4.4 grams of the thread mentioned in Example 4 are treated for 2 hours at a pH value of 8.5 and a goods-toliquor ratio of 1:50 in a bath containing 12% of pamino-diphenylamine, 4 grams/liter of o-phenylphenol, 1.5 gram/liter of an anion active alkyl-phenylpolyglycol ether sulfate and 0.5 gram/liter of glue. The oxidation takes place after an intermediate rinsing at a goods-toliquor ratio of 1:50 in a bath containing 0.41 gram of Nchlorsuccinimide with a content of 0.34 gram of active chlorine per gram of substance. The content of active chlorine corresponds to about 0.7 gram/liter. The oxidation is carried out for 20 minutes at C. in the presence of a slight amount of ammonium vanadate as accelerator. A very deep black dyeing is obtained.

Example 9 3.25 grams of a hand knitting yarn consisting of polyethyleneglycol terephthalate fiber (fiber thickness 3.75 deniers, staple length 70 mm, yarn thickness Nm. 18/3, twist Z 210/ S 150) are preliminarily treated for 2 hours as indicated in Example 8, 3 grams/liter of o-phenylphenol, however, being introduced as auxiliary dyeing agent. After a short intermediate rinsing the oxidation takes place at a goods-to-liquor ratio of 1:50 in a bath containing 1.43 grams/liter of sodium chlorite of 70% strength and adjusted to a pH of 3.5 by means of formic acid. The material is treated for 20 minutes at the boiling temperature. A black dyeing of very good fastness properties is obtained.

Example 10 3.16 grams of endless threads consisting of polyethylene glycol terephthalate thermally fixed for 30 seconds with tension at 220 C. are dyed at the boil for two hours in a bath charged with 15% of p-amino-diphenylamine, 3 grams/ liter of o-phenylphenol, 1.5 grams/ liter of an anion active alkylphenyl polyglycol ether sulfate and 0.5 gram/liter of glue and showing a pH value of 8.5 and a goods-to-liquor ratio of 1:50. After an intermediate rinsing the dyeing is developed at a goods-toliquor ratio of 1:50 at a temperature of 90 C. for 15 minutes in a bath containing 5 grams/liter of toluene-4- sulfonic acid-N-chloramide sodium. A black dyeing is obtained which shows a greenish tint.

Example 11 4.24 grams of the thread described in Example 2 are introduced at 60 C. and a goods-to-liquor ratio of 1:50 into a bath containing 1.5 grams/liter of an anion active alkylphenyl-polyglycol ether sulfate and 15% of p-aminodiphenylamine. The material is treated for 3 hours at C. under pressure, and the dyeing is subsequently developed by means of 4 grams/liter of the sodium salt of toluene-4-sulfonic acid-N-chloramide at a pH value of 4 and a temperature of 9095 C. A deep black a dyeing resisting to humidity and rubbing is obtained which is excellently resisting to light.

Example 12 4.17 grams of the thread mentioned in Example 1 are pretreated in the manner described in this example by means of p-amino-diphenylamine, are then oxidized in the presence of a slight amount of ammonium vanadate at a goods-to-liquor ratio of 1:50 and at a pH of 4 by means of 0.78 gram of benzoic acid-N-dichloramide which is dispersed by means of an alkylphenyl polyglycol ether sulfate. The benzoic acid-N-dichlorarnide contains per gram 0.32 gram of active chlorine. The goods are introduced into the oxidation bath at a temperature of 60 C., the temperature is then gradually raised to the boiling point and the dyeing is finally developed for 15 minutes at the boil. A black dyeing is obtained which shows a bluish tint.

Example 13 Unstretched, endless material of polyethylene glycol terephthalate (single titer about 12 deniers) is preliminarily treated at a temperature progressing from 60 to 95 C. with of p-amino-diphenylarnine dispersed by means of 1.5 grams/liter of an alkylphenyl-polyglycol ether sulfate and a small amount of glue and oxidized with 4 grams/liter of the sodium salt of toluene-4-sulfonic acid-N-chloramide in a bath adjusted to a pH of 4 by means of acetic acid. A very intense, deep, pure black dyeing is obtained.

Example 14 4.33 grams of the thread indicated in Example 4 are treated in a bath containing 12% of p-amino-diphenylamine, 3% of 1.5-diamino-naphthalene, 1.5 grams of an anion active alkylphenyl-polyglycol ether sulfate and 0.5 gram/liter of glue. As carrier there are still added 3 grams/liter of o-phenyl-phenol. The dyeing and the oxidation are carried out in the manner described in Example 1. It results a deep, pure black dyeing.

The same shade is obtained by replacing the 1.5-diamino-naphthalene by 4-amino-l-phenylamino-naphthalene, while by the use of the same amount of 1.8-diaminonaphthalene the tint becomes more reddish.

Example 15 An endless spinning cable, stretched after spinning in a ratio of 1:2 and consisting of polyethylene glycol terephthalate, individual titer 6, is preliminarily treated for 1 hour as indicated in Example 13 with 10% of aminodiphenylamine, dispersed with 1.5 gram/liter of alkylphcnyl-polyglycol ether sulfate and a slight amount of glue, at a pH value of 8.5 and at a temperature progressing from 80 to 100 C. The oxidation is then carried out for minutes in a bath containing 4 grams/liter of the sodium salt of toluene-4-sulfonic acid-N-chloramide and adjusted to a pH value of 4 by means of acetic acid. A good black dyeing is obtained which shows a bluish tint. The dyed thread can subsequently be further oriented, even at room temperature.

Example 16 A worsted yarn consisting of 100% of polyethylene glycol terephthalate fiber and thermally fixed at 195 C. is treated at a goods to-liquor ratio of 1:50 in a bath containing in a dispersed state per liter 2 grams of diphenyl oxide, 3 grams of disodium phosphate, 0.5 gram of monostearoylamido-ethylene -t1imethyl ammonium-methosulfate and 12% of p-amino-diphenylamine (referred to the goods). The base is applied within 1 /2 hours at the boiling temperature, the pH Value having been increased gradually from 5 to 9 by addition of sodium hydroxide solution of 10% strength. After a thorough rinsing with water of room temperature the oxidation takes place within minutes at the boiling temperature in a bath containing 3 grams/liter of the sodium salt of toluene-4- sulfonic acid-N-chloramide and adjusted to a pH value S of 5.1 by means of acetic acid. Subsequently the goods were washed at the boil in a bath showing a pH value of 7.5 and containing per liter 0.5 gram of alkylphenyl-polyglycol ether and 0.5 gram of hydrogen peroxide of 30% strength. The goods show a deep, neutral black tint.

If, instead of monostearoyl-amidoethylene-tri-methylammonium-methosulfate 2 grams of stearoyl-amidopropyldimethyl-fi-hydroxyethyl ammonium dihydrogen phosphate are used, while carrying out the dyeing in the same manner, a very deep black dyeing is obtained also in this case.

The same result is obtained by using as cation active agent 1 gram of N-octedecyl-acetamide-w-pyridinium chloride per liter.

Example 17 The hand knitting yarn described in Example 9 is dyed and further treated as described in Example 16 by means of 12% of p-amino-diphenylamine in the presence of 0.5 gram of N-octadecyl-N-dimethyl-aminopropyl-aminourea. A completely uniform black dyeing is obtained. The dyeing bath remains clear without precipitation.

If, instead of the urea, palmitic acid-N-y-dimethylamino-propylamide is used, an addition of about 1.5 gram is necessary in order to obtain a stable base solution.

We claim:

1. A process for preparing fast black dyeings on textile material of polyethylene terephthalate which comprises applying to said material a black base of the formula wherein R is a member of the group consisting of H, CH and NH and R is a member of the group consisting of H and OCH and oxidizing said base with a member of the group consisting of (a) benzene sulfonic acid chloramides of the formula wherein X is a member of the group consisting of H and Cl, Y is a member of the group consisting of H, CH and Cl, and Z is a member of the group consisting of H and SO NC1X, (b) benzoic acid-N-dichloramide, and (c) N- bromo and N-chloro-succinimides.

2. A process as claimed in claim 1, wherein the black base is applied on the fiber in the presence of carrier.

3. A process as claimed in claim 1, wherein the black base is caused to act on the fiber in the form of a dispersron.

4. A process as claimed in claim 1, wherein as black base p-amino-diphenylamine is used.

5. A process as claimed in claim 1, wherein diphenylene oxide is used as carrier.

6. A process as claimed in claim 1, wherein a cationic dispersing agent containing amide groups is used for the dispersion of the black base.

7. A process as defined in claim 1, wherein toluene-4- sulfonic acid chloramide is used as oxidation agent.

8. Textile material consisting of polyethylene tereph-thalate fibers dyed black by the process of claim 1.

9. A process for preparing fast black dyeings on textile material of polyethylene terephthalate which comprises applying to said material a black base of the formula wherein R is a member of the group consisting of H, CH and NH and R is a member of the group consisting of 9 10 H and OCH and oxidizing said base, first at a temperain which R is a member of the group consisting of H, ture of 30 to 70 C. with a hypochlorite of the group con- CH and OCH naphthylamines of the formula sisting of alkali metal and alkaline earth metal hypochlorites, and then at a higher temperature in the range of 60 to 100 C. with a member of the group consisting of 5 R4 N (a) benzene sulfonic acid chloramides of the formula Y in which R; is a member of the group consisting of H, NH and phenylamino, and phenylamines of the formula SOQNCI 10 z a Q- wherein X is a member of the group consisting of H and wherein R is a member of the group consisting of NH,; Cl, Y is a member of the group consisting of H, CH and 1 and OH. Cl, and Z is a member of the group consisting of H and 5 SO NCIX, (b) benzoic acid-N-dichloramide, and (c) N- References Cited in the file of this patent bromo and Nchloro-succinimides. FOREIGN PA 10. A process as defined in claim 1 wherein the black base is applied in combination with a base of the group 20 255962 Great Bntam 1926 consisting of diphenylamines of the formula O H REFERENCES Ra NH: Textile Manufacturer, December 1949, pp. 590591.

22 American Dyestuif Reporter, Nov. 13, 1950, page 790. Fern: Journal of the Society of Dyestuff Chemists,

R3 25 December 1955, pages 846-854. 

1. A PROCESS FOR PREPARING FAST BLACK DYEINGS ON TEXTILE MATERIAL OF POLYETHYLENE TEREPHTHALATE WHICH COMPRISES APPLYING TO SAID MATERIAL A BLACK BASE OF THE FORMULA 